Laying Subfloor for New Bathroom Question

I am planning to install a bathroom (toilet and sink only) on our main level above the basement. It is going in a hallway where the stairs used to be. (previous owner moved for some reason) The hallway is about 10' long (perpendicular to joists) by 3' wide. We are eventually going to put down hardwood floors but this is down the road a ways...lots to do on the house and redoing the floors is not a priority, however we DO need a bathroom on the main level. In the mean time we are going to set the toilet on the subfloor then re set it when we put down the hardwood.

My first question is should I use plywood, or is there something special I need to do because this is a bathroom w/ moisture and all?

My second question is about subfloor spacing. Do I need a gap between joints? There are only going to be really one joint because it is such a small area, but I have read to leave 1/8" space between the two plywood pieces above a joist to allow for expansion.

Thirdly, how close to the walls should I put the subfloor? Do I need a gap there, or should I cut it as close as possible?

Lastly, any issue w/ leaving the flooring unfinished, and just putting the toilet on the subfloor then adding hardwood later? We just want a toilet for now so we don't have to run upstairs to use the bathroom every time we need to go. Will this cause an issue when I add the hardwood where the toilet drain pipe will be sunk down too far because of the thickness of the hardwood?

Thanks,

Richard

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Laying Subfloor for New Bathroom Question

You need to make sure the toilet ring on the floor is off the plywood 3/4" or the thickness of the flooring to be installed. If not you could have a problem installing the toilet after the floor goes in. If you are going to install hardwood flooring most installers put felt paper over the subfloor, then install the floor.

Plywood is acceptable, yes leave a little gap and plywood as close to the wall as possible. Hope this helps

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Laying Subfloor for New Bathroom Question

Plywood will definitely work, make sure however that you don't miss some other detail when installing the floors. Here are my 13 steps to floor installation. Hope this helps. Good luck with your project.
1. First, mark guidelines on the subfloor and do a “dry run,” during which you lay the tiles without adhesives to see how they lay and fit. For square rooms, find the center of the room and mark the guidelines from each wall. For rooms of any other shape, use a chalk line to snap a marker perpendicular to the main entrance to the room. Apply hairspray to prevent smudging or erasing of the line, and use a square measure to make sure the line is perpendicular to the entrance. You will start laying full tiles at the entrance because a visible full row of tiles greeting guests is preferable to pieces and offers a more balanced visual.
2. From the entrance to the farthest wall, lay tiles along the line you snapped. Make sure the tiles abut to one another, or use a spacer to ensure equal distance between tiles.
3. When you reach the end of the room and there is no longer space for a full tile, mark off the remaining space with a piece of wood or other marker. Tack this into place and continue to dry lay tiles in both directions to the walls on each side of the room, making a “T” shape with the tiles. Stay one tile away from each wall or obstacle.
4. For equal-sized border tiles, determine how much space you have left over at the end of each tile line, and shift the tiles you laid to make sure that the leftover space is equal on both sides of the room. Snap a second line based on this measurement in one corner, and where this line intersects with the wood or other marker is your new starting point. The first line is no longer needed, so the dry-set tiles can be removed for the moment.
5. Using a 1/16” notched trowel, lay a two-foot square area of adhesive in the starting corner. Follow directions on the adhesive packaging as some adhesives have a window of as few as five minutes to set any tile!
6. As you lay down the tiles, work them into the adhesive to make sure they are flush. Keep going in two-foot increments so the adhesive doesn’t dry out. Work your way back and forth across the room.
7. Roll as you go with a 150-pound roller that can be rented for about $20 per day. Keep rolling until the tile has set and completely bonded to the adhesive.
8. To lay the border tile, lay another full tile over the last full tile. Mark a line across the top tile, and make sure you use a spacer against the wall. This is called “jump scribing,” and denotes where you need to cut the border tile.
9. Cut border tiles with a diamond-edged wet saw (for clean lines and less dust) glasscutter, or straight edge tile cutter. Snap off the border piece against a workbench or use tile nippers.
10. Lay and set the border tiles.
11. Make sure to tile under heavy appliances such as dishwashers. Many people skip this step, but it can prove faulty and expensive. If there’s a leak underneath the appliance, the moisture seeps and ruins the subfloor underneath the entire tile job, causing buckling and cracking. If the tile is laid completely underneath, then you quickly realize any leaks and can take necessary and effective action.
12. After you lay all the tiles, begin the grouting process. Follow the directions, and mix the grout according to the manufacturer’s recommendations. Apply the grout with a rubber floater at a 45-degree angle into the spaces between the tiles.
13. Wipe off excess grout with a sponge and take care not to dig grout of the spaces between the tiles. To help the grout become a solid, resilient surface, mop the floor daily for three days. Allow the grout to cure for a week and then brush the grout with a silicone sealer.